When metals are placed under load at high temperature they usually deform over time; a process known as creep. In this experiment we will look at the creep behaviour of a type of stainless steel that is commonly used to make nuclear reactor parts, and specifically at how this material behaves when it is loaded in several different directions at once. This is important because in real reactor components the steel very often experiences this sort of multi-axial loading and creep limits the service life of the reactor. We will measure small deviations in the creep behaviour of the material and try to link these changes with stresses in the microscopic metal crystals that make up the steel. This will allow creep under multi-axial loading to be predicted more precisely in the future, which should allow engineers to assess the integrity of high-temperature structures more accurately.